Sheaths for thermometers or other probes are well known and in commercial use, being used to protect against any cross-infection from one patient to another by the reuse of incompletely sterilized glass thermometers or the like. Examples of such sheaths are as illustrated in the pending patent applications of Harry Bala, specifically U.S. application Ser. No. 205,316, filed June 10, 1988 and entitled Sheath for Probe, and U.S. application Ser. No. 212,969, filed June 29, 1988 and entitled Sheath for Thermometer and the Like.
The probe sheaths of the prior art are typically made in flattened form out of a pair of flat sides which are peripherally sealed together with the probe sheath being enclosed in a package. This of course requires the use of plastic sheeting which heat seals together in a reliable manner, such as polyethylene or poly(ethyl-methyl acrylate), also known as EMA. Additionally, poly(ethylenevinyl acetate) (EVA) or equivalent material may be used.
The probe sheaths of the prior art perform adequately to provide a sealed sheath around oral or anal thermometers in normal circumstances. However, in the rare but unfortunate circumstance where an accident or an unruly patient breaks the thermometer during use, the probe sheaths of the prior art are sometimes of insufficient strength to avoid rupturing. This can, of course, cause shards of thermometer and mercury to pass into the patient. Additionally, the major purpose of the probe sheath may then fail, that is, the protection of the patient from bacterial or viral exposure from an incompletely sterilized thermometer or other probe. Particularly in the case of small children or certain disabled patients, the patients may bite through the probe sheaths of the prior art while the thermometer or other probes are inserted in the mouth, resulting in possible viral or bacterial exposure to the patient.
In accordance with this invention, an improved probe sheath is provided in which a reliable heat seal is provided to the probe sheath, but the sheath is of a strength which is capable of substantially preventing bite-through in the mouth when enclosing a glass thermometer or other probe.
While certain plastic materials are known to be much stronger than polyethylene, EMA, or EVA, such materials are generally less effective in heat sealing. For example, biaxially oriented poly(ethylene terephthalate) or polypropylene are very strong materials, but they are heat sealed only with difficulty to each other, so that a flattened probe sheath of the type typically used made of such materials would be unreliable due to the possibility of failure of the peripheral heat seal during use.
In accordance with this invention, an improved probe sheath is provided which combines both the necessary good heat sealing of peripherally connected flat sides of the probe sheath with a desired strength that is sufficient to substantially prevent bite-through in the human mouth. With such an increase in strength, the probe sheath is also much more reliable for protection against breakage of a glass thermometer being used, and also increased protection against bacterial or viral exposure is provided.